Google Play, which was known as the Android Market until March, hit the milestone in 1,435 days -- three years and 11 months. By contrast, Apple's App Store reached 25 billion downloads in 1,334 days -- just under three years and eight months.

"We look forward to the next 25 billion," the company said in a blog post.

To mark the occasion, Google will discount a variety of popular apps. Participating developers include Gameloft, Electronic Arts, Rovio, runtastic, Full Fat -- and their apps will be on sale for 25 cents apiece.

The company is also promoting collections like 25 must-own movies, 25 banned books and "25 albums that changed the world." All will be offered at discounts.

Clearly Google Play has transformed into one of the most popular places in the world for downloading software. Now if only developers could get Android users to start paying for that software, Google will really have something to crow about.